I am not related, but have you considered that Susan may have been previously married before her relationship with John?
I see that they spent some time in NSW before going to Queensland and their son Ebenezer's birth was registered as WALTERS and also as JEFFERY with no father named.
Marriage in NSW:
James HENNING and Mary Ellen MIDDLETON married at Liverpool, Lancashire in 1841. They had a daughter Susannah whose birth was registered in 1842 at Liverpool and they arrived in NSW on the "Elizabeth" in 1844.
I wonder if John WALTER's parents are actually Walter WALTERS and Salome PRITCHARD, rather than Mahomey PRICE?
There is quite a bit of circumstancial evidence. Walter and Salome married in Staffordshire in 1834, they had children in Staffordshire (John and William)and at Monmouth in Wales (Sarah Agnes) and perhaps are the same couple who came to Australia and had children Harriet (1846) and Ebenezer (1850) in NSW. At some stage they also had a son named Walter S. who died in 1905 in Newcastle. It looks like both Walter Snr.and Salome also died in Newcastle.
Something to think about.